Technologue: Hot Hybrids

Green technology lets its hair down

Electric and hybrid cars were so ubiquitous on the Geneva motor show stand that an electrically powered Transformers robot could've stomped from one end of the floor to the other crushing nothing but electrically boosted vehicles. But this time the news wasn't all just for tree-huggers' consumption. Three of Europe's greatest sports car brands revealed hybrid designs that are optimized for performance at least as much as they are for fuel economy.Naturally Lotus' Chevy Volt-style plug-in Evora 414E Hybrid strives to reduce weight above all else. The existing aluminum architecture is pretty feathery to start with, which helps shrink the size of the lithium-polymer battery required for the target 35-mile electric range to 17 kilowatt-hours. Lotus' range-extending three-cylinder engine integrates the block, head, and exhaust manifold in one casting to reduce engine mass (to just 187 pounds, dressed), assembly costs, and package size. It's also said to improve emissions and engine durability. The two-valve-per-cylinder, port-injected engine runs on gasoline, ethanol, or methanol. With an electric motor powering each rear wheel, the electronics can provide torque vectoring for even sharper cornering. Harman International co-developed a HALOsonic engine-sound generating system that plays through the stereo speakers and two exterior ones (for pedestrian awareness). Available soundtracks include V-6, V-12, "futuristic" (think Tron bikes), or a combination Tron/V-12. With help from HALOsonic, paddle-shifters can make the single-speed tranny feel like a seven-speed (mostly useful for tailoring the amount of regen provided during deceleration).Porsche's show-stopping 918 Spyder plug-in parallel hybrid also mounts a pair of torque-vectoring motors on the front axle (plus one on the transaxle), with a power-boost button on the steering wheel for short bursts of electric assist. This reportedly helps it lap the Nurburgring Nordschleife quicker than a Carrera GT (under 7:30). But of greater interest here was the GT3 RS Hybrid race car's flywheel generator system, which is electrically connected to a pair of 80-horsepower motors on the front axle capable of contributing six to eight seconds of torque-vectoring acceleration to hasten corner exits. The lightweight compact flywheel is able to absorb more braking energy and deliver more power quicker than a chemical battery can. It fits where the passenger seat would go, and it's small and light enough that its aluminum housing can contain a catastrophic failure at its top speed of 40,000 rpm. The whole system adds 287 pounds.Finally, Ferrari's 599 Hy-KERS concept investigates hybridizing as a means of lowering city CO2 emissions by fitting an electric motor to the odd-gear shaft of its new dual-clutch transmission. Continuous electric assist is provided by shifting the odd gears to neutral and reengaging that clutch while engine power flows through an even gear. An electric motor in front powers the accessories so that the 3kWH battery can provide six miles of electric operation on the Euro city cycle. To minimize weight, Ferrari eliminates the starter and main 12-volt battery (a small battery maintains the electronics and wakes the system up) for a net gain of 176 pounds. The team plans to investigate using the electric motor to help match engine revs during shifting, to counteract vibration resonance in the transmission during acceleration, and possibly to reduce weight further by ditching the reverse gears and shrinking the rear brakes. It's nice to know technologies like Kinetic Energy Recovery Systems don't have to succeed in Formula 1 to benefit road cars.